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        검색결과 13,059

        5961.
        2008.05 구독 인증기관 무료, 개인회원 유료
        본 연구는 델파이 방법을 적용하여 전문가의 의견을 수렴하여 국가의 기술 및 연구개발 정책을 결정할 때 델파이 방법의 단점인 전문가의 합의된 의견이 틀리는 부분을 보완해서 검증할 수 있는 방안을 제시한다 본 연구에서 제안한 방법은 . 델파이 방법을 사용하여 기술 예측을 하는 경우 특허 문서와 같은 대상 기술 분야의 기술에 대한 분석을 수행하여 두가지 방법을 통해 나온 결과를 상호 비교 분석하여 델파이 방법의 결과의 타당성을 검증토록 한다.
        3,000원
        5962.
        2008.05 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        Pure Mg and Mg-6wt.%Al alloy were coated by the plasma electrolytic oxidation with various coating times and the microstructural and mechanical characteristics of the coatings were investigated. The coatings on pure Mg and Mg-6wt.%Al alloy consisted of MgO and Mg2SiO4. The surface roughness and thickness of the coatings became larger as the coating time increased. The coatings on the Mg-6wt.%Al alloy were more uniform and thicker than those on pure Mg. The microhardness and friction coefficient of the coatings increased progressively as the coating time increased. In addition, the coatings on the Mg-6wt.%Al alloy compared to pure Mg showed improved microhardness and a better friction coefficient.
        4,000원
        5963.
        2008.05 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        Porous Ti implant samples were fabricated by the sintering of spherical Ti powders in a high vacuum furnace. To increase their surface area and biocompatibility, anodic oxidation and a hydrothermal treatment were then applied. Electrolytes in a mixture of glycerophosphate and calcium acetate were used for the anodizing treatment. The resulting oxide layer was found to have precipitated in the phase form of anatase TiO2 and nano-scaled hydroxyapatite on the porous Ti implant surface. The porous Ti implant can be modified via an anodic oxidation method and a hydrothermal treatment for the enhancement of the bioactivity, and current multi-surface treatments can be applied for use in a dental implant system.
        4,000원
        5964.
        2008.05 KCI 등재 구독 인증기관 무료, 개인회원 유료
        In this study it will be discussed how to solve the problem of discomfort from rolling motion on the fishing boats. Most discomfort is caused by the short cycle of rolling due to the light weight of the boats. The light weight is due to the FRP material which dries a boat. A way to improve the feeling of boarding by using fish hold was researched. The experiment was done on experimental fishing boat made by FRP in Jeju. An existing fish hold was designed and manufactured through the rolling test and that was used for a marine experiment. The rolling condition of the U-tank boat ideally designed was compared to that of an existing fishing boat using the same conditions. The experiments were carried out two times on the stop engine in the outward Sehwa fishing port, which the experimental data had analysed for effects of rolling reduction to compare the U - tank with the of exiting fish hold. The results were confirmed that the U-boat tank in the roll period and GoM were more safe than the existing fish hold and the average amplitude and significant of rolling angles were decreased relatively.
        4,000원
        5965.
        2008.05 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study was performed to estimate biomass and to provide management plan through population ecological characteristics, including growth parameters, survival rate, instantaneous coefficient of natural and fishing mortalities, and age at first capture of hen clam, Mactra chinensis, in the Dong-li self-regulatory community of Busan. The von Bertalanffy growth parameters estimated from a non-linear regression were SH∞=86.24mm, K=0.12/year, and = -1.37year. Survival rate(s) of the hen clam was 0.515. The instantaneous coefficients of natural mortality(M) was estimated to be 0.232/year and fishing mortality(F) 0.432/year for hen clam. The current biomass of the hen clam in the study area was estimated to be 713mt and the acceptable biological catch(ABC) was estimated under various harvest strategies based on F0.1 and F40%.
        4,300원
        5966.
        2008.05 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Estimation of the gear shape and cross section of sweep at mouth of a bottom trawl net was described and applied to the field experiments obtained with the Scanmar system. The shape of the trawl net from wingend to the beginning of codend was assumed to be part of an elliptic cone of which the cross section was ellipse, and that of the float rope be of form yf=afxbf. In case of a bottom trawl with warp 180m long, the radius of ellipse, the cross section of sweep at mouth, the eccentricity of the ellipse, the inclination angle of float rope and the contribution of the side panel to net height were estimated in accordance with towing speed. The horizontal radius of the upper ellipse increased with increasing towing speed, the eccentricity of it became slightly bigger as increasing the towing speed which meant the shape of it being flat. And the inclination angle of the float rope was about between 7 and 12 degrees in case of the above bottom trawl.
        4,000원
        5967.
        2008.05 구독 인증기관 무료, 개인회원 유료
        가변단면 압출기술은 사용하는 금형의 조합에 의해 다양한 가공이 가능한 성형공법으로, 압출시에 금형의 움직임에 의하여 제품의 단면형상을 변화시키거나, 치수와 두께를 동시에 변화시킬 수 있다. 압출공정에서 압출속도, 압출압력, 압출온도는 압출품의 표면결함이나 내부품질에 있어 중요한 영향인자이다. 그중 일정한 압출속도는 균일한 메탈 플로를 형성하여 성형품질에 있어서 고른 상태를 유지하게 만드는 요소이다. 기존의 압출 성형에서 펌프토출양의 변화에 의한 추출속도변동 문제는 램 속도의 변화를 계측하고 토출 양을 조정함으로써 압출속도를 제어하는 방법으로 해결한다. 그러나 가변단면 압출공정에서는 제품의 단면형상의 변화에 따라 압출비가 변하므로 이에 따른 램 속도 제어가 있어야만 한다. 본 연구에서는 가변단면 압출공정에서 가공형상에 따른 제어 알고리즘을 제시하여 가변 형상에 따른 램의 이동 속도 및 위치를 제공하려 한다.
        4,000원
        5968.
        2008.05 KCI 등재 구독 인증기관 무료, 개인회원 유료
        목적 : 본 연구는 만 3-6세의 일반아동과 발달장애아동을 대상으로 감각처리능력에 영향을 미치는 요인을 알아보기 위하여 실시되었다. 연구방법 : 발달장애아동 111명과 일반아동 135명의 주 양육자를 대상으로 설문조사를 실시하였다. 설문지는 아동의 감각처리능력에 영향을 미칠 수 있는 내적 요인과 외적 요인에 관한 문항, 그리고 단축형 감각 프로파일에 관한 문항으로 총 95문항이었다. 수집된 자료는 SPSS를 이용하여 통계처리하였고, 일반아동과 발달장애아동의 내외적 요인은 기술통계, 그룹 별 감각처리능력은 독립표본 t-검정, 그리고 감각처리능력에 영향을 미치는 요인 분석은 단계적 다중 회귀분석을 사용하였다.결과 : 발달장애아동에서 감각처리능력의 평균 점수는 135.37±21.17점이었고, 일반아동에서 평균 점수는 165.02±16.69점으로 두 그룹에서 통계적으로 유의한 차이가 있었다. 발달장애아동의 감각처리능력에 영향을 미치는 요인은 아동 기질의 정서성과 또래관계이었다. 일반아동은 아동의 출생 시 몸무게와 기질의 정서성이 감각처리능력에 영향을 미치는 요인이었다.
        4,600원
        5979.
        2008.05 KCI 등재 구독 인증기관 무료, 개인회원 유료
        With the introduction of the video display terminal (VDT), the efficiency and productivity of work has improved. However, VDT syndrome is threatening the health of workers as a side effect of prolonged use of a VDT. Among various VDT syndromes, the musculoskeletal disorder, especially, the cumulative trauma disorder (CTD) is the common research topic related with upper extremities function. The aim of this study was to investigate the effect of the wrist-hand orthosis (WHO) on fatigue in middle deltoid, anterior deltoid, serratus anterior, and upper trapezius during one-hour computer keyboard typing. Twelve healthy subjects participated in this study. Surface electromyography was used to assess the localized muscle fatigue (LMF), and the LMF was calculated at 10 minutes, 20 minutes, 40 minutes, and 60 minutes in each muscle, with and without the WHO. Data were analyzed by paired t-test with a level of significance of .05. The results of this study are as follows: 1) At 10 minutes, the LMF decreased significantly with applied WHO in the middle deltoid, anterior deltoid, and upper trapezius (p=.001, p=.026, p=.019, respectively). 2) As the computer keyboard typing period increased, there were no significant LMF differences, except for the upper trapezius. Therefore, it can be concluded that the WHO can be applied to decrease the LMF for the initial 10 minute period in the middle deltoid, anterior deltoid, and upper trapezius' but that the long term effect of WHO in reducing the LMF was proven only in upper trapezius during continued computer keyboard typing.
        4,000원
        5980.
        2008.05 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The purpose of this study was to determine the differences in joint moment in the intact limb of uni-transfemoral amputees and to identify the implications of knee osteoarthritis. As an experimental method, three-dimensional gait analysis was performed on 10 uni-transfemoral amputees and 10 healthy males. Kinematics and kinetics at the hip, knee, and ankle joint were calculated. As a statistical method, independent t-tests were conducted to perform a comparison between the transfemoral amputee group and the control group. The results showed that the external knee adduction moment increased in the transfemoral amputee group (.22 Nm/kg) compared with that of the control group (.13 Nm/kg) at terminal stance (p=.008). External knee flexion moment also increased in the transfemoral amputee group (.24 Nm/kg) but this difference was not statistically significant. External hip flexion moment increased in the transfemoral amputee group (1.35 Nm/kg) compared with that of the control group (.45 Nm/kg) at initial stance, and external hip extension moment decreased in the transfemoral amputee group (-.26 Nm/kg) compared with that of the control group (-.76 Nm/kg) at terminal stance. Although external ankle plantarflexion moment of the transfemoral amputee group increased, it was not found to be statistically significant. The results suggest that the intact limb joint moment of the uni-transfemoral amputees during walking can be different from that of healthy subjects. In conclusion, it was found that there is a link between the increase of external knee adduction moment and the prevalence of knee osteoarthritis in uni-transfemoral amputees. This result is expected to provide some objective data for rehabilitation programs related to knee osteoarthritis in transfemoral amputees.
        4,000원